This type of craft toy Tim refers to as a 'musical bee' although they come with different pictures on them. This version, made in the USA, has a 1960s style rocket printed on it, and is called The Rocket Ship.
There is a piece of card, which is strengthened by the addition of a strip of wood at one side. An elastic band is stretched around the piece of wood in such a way that there is a strip of elastic that is free to vibrate on either side. You can also adjust the tension so that the two lengths of elastic have slightly different amounts of tension in them, which makes them vibrate at slightly different frequencies, i.e. two different notes.
The whole thing is attached to a piece of fine thread, and when you whirl it through the air, it vibrates, producing a musical noise or hum. A bit like a bee really!
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